1. Field of the Invention
The present invention relates to multiple-barreled devices for mixing together and dispensing viscous substances. More particularly, the invention relates to a double-barreled syringe having a double-barreled plunger of unitary construction for dispensing an admixture formed when two gels stored in the barrels are simultaneously discharged into a mixing tip having a five section static mixing element. The tip, which interlocks with the syringe body, is detachable and may be replaced by a locking closure cap to prevent leakage when the syringe is not in use. The locking closure cap preferably has a liner which mitigates undesirable leakage during transport and storage.
2. Description of the Related Art
Devices for mixing and dispensing a viscous fluid having separately stored constituents wherein a mixing portion is detachably connected to a storage portion are known in the art. U.S. Pat. No. 5,413,253 to C. Simmen discloses a static mixer for connection to a cartridge having at least two chambers containing different materials. The mixer is connected to the cartridge by inserting hollow circular make prongs and arcuate positioning keys of a center plug within corresponding female outlets in the cartridge. The plug is rotatably mounted within the collar of a sleeve. The mixer is locked to the cartridge by rotating the collar until opposed tabs on the sleeve engage with locking arms on the dispensing end of the cartridge.
U.S. Pat. No. 4,538,920 to G. E. Drake discloses a double-barreled syringe for mixing and dispensing a two-component material such as a resin and its hardener. Both a mixing tip and a static mixing element located within the tip bore are flexibly rotationally aligned with the syringe body so that the first blade of the mixing element is generally perpendicular to the plane of contiguity between the two component streams exiting a syringe body outlet. The mixing tip is connected to the body by centering the tip inlet over the body outlet while aligning the tip so that it can be pushed between opposed bayonet locking tabs, each having a prong and a stop surface, and then rotating the tip so that opposed ramps on the tip inlet end are wedged between the prongs, and a stop surface proximate to each ramp engages a tab stop surface.
Although either of these devices enables the storage and mixing portions to be connected and then detached multiple times, both are so complex as to be unsuitable for mass production of inexpensive, throwaway dispensers. What is needed is a device which on demand can thoroughly mix two-component viscous materials and dispense a desired amount of the admixture, which will not leak when set aside, and which can be mass produced at relatively little cost.
Accordingly, it is an object of the present invention to provide a simple, reliable and convenient device which simultaneously dispenses equal amounts of two well mixed viscous materials as an admixture.
Another object of the invention is to provide a device which can be repetitively used to dispense desired amounts of an admixture.
A further object of the invention is to provide a device having a storage portion and a mixing-dispensing portion which repetitively can be easily connected and then detached, wherein the storage portion does not leak during storage and transport thereof.
A still further object of the invention is to provide a device that is inexpensive to manufacture.
Other objects of the invention will become evident when the following description is considered with the accompanying drawing figures. In the figures and description, numerals indicate the various features of the invention, like numerals referring to like features throughout both the drawings and the descriptions.
These and other objects are achieved by the present invention which provides a double-barreled syringe wherein one barrel contains a hydrogen peroxide water-based gel formulation used for teeth whitening, and the other contains a gel formulation including compounds that will accelerate the release of oxygen from the first formulation and consequently increase the reaction rate of the teeth whitening process. The syringe dispenses an admixture formed when the two formulations are simultaneously discharged into a mixing tip having a static mixing element. The tip, which is in locking connection with the syringe body, is replaced by a locking closure cap to prevent leakage when the syringe is not in use.
The syringe body includes a double-barrel assembly having juxtaposed first and second barrels having a common length and a generally cylindrical bore of a common diameter. Each barrel is bounded at a discharge end by first and second shoulders, respectively, with each shoulder having a generally planar surface. The surfaces are coplanar and contiguous. A generally cylindrical neck extends from and is symmetrically disposed between the shoulders. The neck includes first and second outlet passages. Each barrel at its opposite (plunger) end closely receives a piston within its bore. An arcuately-shaped finger-grip circumscribes the contiguous plunger ends of the barrels.
The syringe body further includes a double-plunger assembly having juxtaposed first and second plungers of a common length. Each plunger extends at a proximal end in an end-piece rigidly attached to one of the pistons, and is rigidly attached at a distal end to a thumb-rest common to the plungers.
Alternatively, each plunger has a seal formed integrally therewith at a distal end thereof. The seal preferably comprises a flare having a wall thickness which is sufficiently thin as to flexibly conform to the bore within which it is contained and thus seal the plunger upon which it is formed with respect to the bore.
Further, according to the preferred embodiment of the present invention an alignment ring is formed proximate the distal end of each plunger. The alignment ring is formed proximal of the seal. The alignment ring enhances alignment of the seal with respect to the barrel within which the seal is disposed. The alignment ring is coupled comparatively flexibly to the shaft of the plunger and the alignment ring is coupled comparatively rigidly to the seal, so as to allow the combination of the alignment ring and the seal to move together as a unit with respect to the shaft while also causing the alignment ring and the seal to remain comparatively fixed in position with respect to one another. In this manner, the alignment ring and the seal remain aligned with respect to the bore within which they are disposed regardless of bending of the shaft of the plunger which may occur during use.
According to the preferred embodiment of the present invention, the alignment ring is attached to the shaft by a first neck and the seal is attached to the alignment ring by a second neck. The first neck has a smaller diameter than the second neck so as to facilitate movement of the combination of the alignment ring and the seal relative to the shaft, while maintaining desired relative alignment of the alignment ring with respect to the seal. Thus, the combination of the alignment ring and the seal tends to move as a unit with respect to the shaft (which may bend independently of the alignment ring and the seal).
The syringe body further includes a first mating assembly having diametrically opposed first and second detents extending outwardly from the neck, and opposed first and second locking ribs symmetrically disposed with respect to the neck and rigidly attached, respectively, to the first and second shoulders. Each rib has a plurality of generally planar locking faces generally parallel to and at a common predetermined distance from the neighboring shoulder surface.
The syringe further includes a generally conical mixing tip hag an inlet end and a discharge end and a bore therethrough. The bore has a generally cylindrical portion at the inlet end and extends in a conically tapered portion toward the discharge end. The cylindrical bore portion is determined by a circumferential surface adapted to closely receive the body neck. A four section static mixing element is closely received and wedged within the bore tapered portion. The mixing tip has at the inlet end a second mating assembly having opposed generally planar, arcuate first and second locking tabs of a common predetermined thickness slightly less than the distance between the rib locking faces of the first mating assembly and the neighboring shoulder. Each tab has at least one edge beveled at a common predetermined angle. The tabs are symmetrically disposed with respect to the cylindrical bore portion. The bore circumferential surface includes diametrically opposed first and second detent recesses and first and second ramps which are contiguous at a proximal end, respectively, to the recesses.
Alternatively, a five section static mixing element is received and wedged within the bore tapered portion. It is believed that the use of a five section static mixing element will provide approximately 50% better mixing than the four section static mixing element. Those skilled in the art will appreciate that additional sections of the static mixing element will provide further enhanced mixing and may therefore be desirable.
According to the preferred embodiment of the present invention, each section of the static mixing element comprises a single turn screw. Each screw is clocked, i.e., configured so as to be right or left handed, opposite that of each adjacent screw and is oriented, with respect to the leading and trailing edges thereof, at 90% with respect to each adjacent screw. Thus, as the two viscous materials flow from one screw to the next screw, the viscous materials are split into two portions, so as to effect desired mixing thereof The screws are disposed upon a common shaft. The screws taper in size such that the viscous materials flow through successively smaller screws as the viscous materials are dispensed.
The first and second mating assemblies are conjoined when the neck is inserted into the cylindrical bore portion in a relative orientation such that each detent contacts a ramp distal end, thereby determining an engaged configuration. The assemblies interlock when the mixing tip is rotated in a first direction until each detent, traversing the ramp and reaching the ramp proximal end, is received within a recess. Concurrently, each tab is closely received between one of the pluralities of rib locking faces and a shoulder. The mating assemblies are detachable when the mixing tip is rotated in the opposite direction until the neck and cylindrical bore portion are in the engaged configuration.
Optionally, a locking closure cap is utilized in place of the mixing tip so as to better mitigate leakage during shipping. The locking closure cap attaches to the body in the same manner as the mixing tip. Preferably, the locking closure cap comprises a locking closure cap liner formed of a comparatively resilient material which provides an enhanced seal between the locking closure cap and the body. The locking closure cap liner preferably comprises a groove formed therein and configured so as to receive a partition formed within the neck of the body.